Development and layout instrument



Sept 10, 1946- G. J. HENJUM 2,407,368l

DEVELOPMENT AND LAYOJIl INSTRIMENT Filed May 22, 1945 INVENroA GERALD J. HENJUM BY www Attorney Patented Sept.v l0, 1946 DEVELOYPMENT AND LAYOUT INSTRUIVIENT Gerald J. Henjum, Hollywood, Calif., assgnor of one-third to Albert H. Farness, North Hollywood, and one-third to Chester H. Sherer, Los

Angeles, Calif.

Application May 22, 1945, Serial No. 595,109

4 Claims.

This invention relates to a new and improved drafting instrument for developing flat patterns of theintersection of surfaces of revolution such as pipes used for uids, and standards or mountings wherein it is desired to develop a Wraparcundtemplate or pattern to facilitate the cutting of the end of a pipe, as when it is desired vto attach a branch pipe'v to another pipe at any angle thereto.

By well known mechanical drafting processes, familiar to engineering draftsmen, it is possible to develop such intersections and patterns or templates on the drawing board, with the use of Yconventional drafting instruments. Such processes are responsible for considerable delayV in'eld and shop work, where the Welder or sheet metal worker desires to do the job on the spot. It is, therefore, an object of this invention to provide a layout instrument capable of use by a mechanic for developing such intersections as needed, at a great saving of time as compared to conventional mechanical drawing procedures. The use of my herein described instrument eliminates the need of computations and the use of conventional drafting instruments, as I provide a series of scales for each standard pipe size to enable the workman to complete the development or layout of a wrap-around pattern or template, Which can be applied directly to the end of the pipeto be cut'or beveled to lit against another pipe at the angle and/or offset contemplated. It is also sometimes convenient to develop a wrap-around template to transfer the outline of the hole to be cut in the pipe to which the branch is to be applied, and this can readily be done with the instrument of my invention.

With these and other objects in view, as will more fully appear as the description proceeds, my invention consists in the construction, novel features and combination of scales hereinafterk more fully described, pointed out in the claims appended, and illustrated in the accompanying drawing wherein:

Figure 1 is a View of one side of a triangle embodying the features of this invention; and,

Figure 2 isa view of the other side thereof.

While I have chosen to illustrate my invention as incorporated in a triangle similar in outline to a conventional draftsmans triangle, it is to be understood that the exact proportions and/or shape of the instrument is immaterial to the principles of my invention, since my coordinated series of scales can be applied to other configuratif-ns without affecting the usefulness thereof.

, edges.

The practical embodiment chosen for illustration comprises a draftsmans triangle lil of conventional outline, having the usual central opening Il whereby the inner edges of the side portions l2, I3 and i4 are parallel to the external In addition, I have sho-Wn a protractor arc l5 having suitable indicia, this feature being useful in setting out the desired anglesat which thepipes `are to be joined.

The coordinated series of scales as shown and hereinbefore referred to, are grouped in various standard pipe sizes, which as is well known, are rated as the nominal inside diameters, varying in this case from one and one-quarter inches to eight inches. In each standard size, I show a scale Yiii marked ID (inside diameter) which represents the successive projections on a diameter of arcs of twenty-two and. one-half degrees, i. e., a semi-circle is divided into eight equal parts, and the projections of these points on the diameter form the scale. For convenience I show only four points plus the center line l'! for a ninety degree arc, as the other four points can be obtained by reversing the triangle and scale. A second scale I8, marked OD (outside diameter) covers four points running the other wayfrom the center line Il, and corresponds to the actual outside diameter of standard pipe of thenominal inside diameter specified. In order to develop a flat pattern of the circumference of a pipe of given nominal size, I provide a third scale I9, marked X, which gives the actual developed length of the arcuate segments divided as in producing the OD scale I8.

In order to be able to strike arcs correspond-'- ing to the actual outside diameters of the several nominal pipe sizes, I provide a series of perforations 20, one oi which is marked as the center O, and the others positioned at the corresponding radii and marked for the nominal pipe sizes.

Inthe use of my layout instrument, the usual mechanical drafting procedure shortened. In the simplest case of a right angled joint between equal sized pipes, it is only necessary to draw two lines at forty-five degrees and to carry the projections of the OD and ID scales normal to one line to their intersection with the other lines, and measure their length on the forty-five degree line, transferring these lengths to ordinates erected at intervals determined by the X scale to develop the layout or wrap-around template for cutting the ends of the pipe. Y

is materially g 3 a specified angle to the main run of pipe, the procedure is a trifle more complicated, but still basically straightforward and readily apparent to those skilled in the art. In order to determine the ordinates to be applied to the layout or Wraparound template lines determined by the X scale for the branch pipe line, it is necessary to draw a base line and strike an arc of the OD of the main run tangent thereto. The amount of offset is marked from the point of tangency and the ID and OD scales centered on the offset, the scale markings being carried down to the arc previously marked, and then carried` out parallel to the base line. The branch pipe center line is drawn at the desired angle and the ID and OD scales marked normal thereto,` being carried down parallel to the center line ofthe branch pipe to intersect the corresponding lines parallel to the base line rst drawn. The lengths of the lines parallel to the center line of the branch pipe form the ordinates of the developed or wrap around template. Y

I find it desirable to use the ID scales for the open sides of the branch pipe, and the OD scales for the closed sides of the pipes, since by so doing the necessity of beveling the cut ends of the pipe isy avoided, and in addition, a V is left for the welding material, in the case of standard pipe which has appreciable Wall thickness. sheet metal, such as stove pipe, the outside diameter is also practically the nominal pipe size, and both ninety degree arcs can be laid out from the ID scales by reversing the triangle about the center line of the scale. However, the illustrated embodiment of the developed length scale I9 allows for appreciable pipe thickness, so that for thin metal the spacings of the flat pattern should be reduced in proportion to the difference between the circumference of standard pipe and the desired circumference of the tubing, by setting the scale at an angle to the base line sufficient to reduce the spacings the required amount.

In the use of the instrument of my invention, the development or wrap-around template may be drawn on any convenient material. If only a single joint is to be made, it may be drawn on paper, which is subsequently wrapped around the pipe and the outline transferred thereto as by prick punching. If a number of duplicate joints are to be made, the template may be drawn on If working with thin-walled tubing or CTI i flexible sheet metal either for transfer direct to the pipe, or as a template for contouring a collar to serve as a guide for cutting the ends of a numn ber of pipes to the same pattern.

Obviously, my invention is susceptible of embodiment in forms other than that chosen for illustration herein, and applicable to other and analogous uses than pipe welding and/or assembling, and I therefore do not desire to be limited other than by the permissible scope of the claims appended hereto.

I claim:

1. A layout instrument embodying a polygonal sheetmaterial having a plurality of scales disposed along the edges thereof, comprising base line projections of equally divided circular arcs corresponding to the inside and outside diameters of a plurality of standard pipe sizes, together with scaies of the developed circumference of similar pipe sizes divided into units corresponding to the spacings of said circular arcs.

2. An instrument adapted to develop the intersections of surfaces of revolution, embodying a member having at least one straight edge, a series of coextensive indicia for at least one circle of a desired diameter marked on said straight edge, comprising a scale of Vbase line projections of uniform divisions of an arc of said circle, and a second scale of the developed lengths of said arcuate divisions.

3. A drafting instrument comprising a plane figure having a plurality of straight edges, and coordinated series of scales marked thereon for a plurality of standard pipe sizes, each set of scales for a particular pipe size including scales of projections of equal arcuate divisions of circles corresponding to the inside and outside diameters of the particular pipe size, and a scale of the developed length of the arcuate divisions of the outside diameter of said pipe size.

4. A layout instrument comprising a triangle having self-contained means for developing the intersection of surfaces of revolution, said means comprising a plurality of scales of base line projections of a plurality of arcuate curves of various radii divided into equal segments, and corresponding scales of the developed length of such arcuate segments for each radius of said rst mentioned scales.

GERALD J. HENJUM. 

